Dr. Ingrid Libman is a pediatric endocrinologist with previous training in epidemiology who is currently an Assistant Professor in Pediatrics at the University of Pittsburgh. The candidate's long term goal is to become an academic physician and independent clinical scientist expanding her training from the area of population based epidemiology of childhood diabetes mellitus (DM) to patient oriented and interventional research, with particular focus on the impact of obesity on type 1 diabetes mellitus (T1 DM), in particular on the development of cardiovascular disease (CVD). This interest developed during the last years when Dr. Libman identified an increase in the prevalence of obesity in this population, usually considered not to be overweight. The consequences of this increase are currently not known. Under the mentorships of Drs. Silva Arslanian, Dorothy Becker, Ronald LaPorte and Bradley Keller, Dr. Libman proposes a comprehensive career development plan composed of training in the use of the hyperinsulinemic-euglycemic clamp to assess insulin resistance, measurement of early CVD markers such as carotid ultrasonography to measure intima media thickness and pulse wave velocity and carefully selected course work in clinical patient-oriented research. The research plan is a three year cross sectional study of three groups of children: overweight children with T1DM, non-overweight children with T1DM and overweight children with no DM in order to compare early risk markers of CVD. This study will also assess the role of insulin resistance, measured by the use of the hyperinsulinemic-euglycemic clamp technique in the first two groups, and validate an insulin resistance syndrome score, consisting of clinical parameters which could potentially be used in clinical and population-based studies. This study will recruit 120 children between the ages of 12 and 18 years who will attend the Pediatric Clinical Translational Research Center (PCTRC) for 24 hours to undergo questionnaire, body anthropometry, blood pressure, fasting blood tests, whole body DEXA, carotid ultrasonography and in the groups with diabetes, an hyper insulinemic-euglycemic clamp. Objectives of the study are to 1) test the hypothesis that overweight children with T1 DM have more markers of early atherosclerosis compared to those with T1DM who are not overweight and to those equally overweight with no diabetes and this is mediated by factors which constitute the metabolic syndrome and 2) assess the role of insulin resistance. (End of Abstract)